1. Field of the Invention
This invention relates to an information processing apparatus in which picture quality is capable of being adjusted at user's requirements.
2. Prior Art
In information processing apparatus such as copying machines and printers, generally a variety of measures are taken in order to maintain the quality of an outputted image at a fixed level. As one example, an apparatus of the aforementioned kind may be provided with control means for directly controlling picture quality, wherein control parameters are set in the control means in appropriate fashion. In addition, the apparatus may be equipped with various sensors in order to optimize the control parameters in conformity with changes in the environment in which the apparatus is used, wherein it is possible to perform highly sophisticated control of the type in which the control parameters are automatically adjusted to appropriate values frequently in dependence upon the outputs from the sensors. For example, in the case of an electrophotographic copying apparatus, control means for so-called development bias control is provided in order to make the copy density, which is an important factor in picture quality, conform to a fixed standard. The control means is so adapted as to set the bias value to a value which is appropriate.
It has recently become possible to perform development bias control more finely. Specifically, accordingly to such control, ambient temperature, ambient humidity, the density of an original document, etc., are sensed by sensors and the appropriate bias values are calculated based upon the sensor outputs in order to stabilize picture quality.
However, in the examples of the prior art described above, ordinarily the values of the control parameters are fixed values decided at the design stage and these cannot be changed following shipment of the apparatus from the factory. Furthermore, in a case where changes in environmental conditions are sensed by a plurality of sensors and the values of the appropriate control parameters are revised, the mapping relationship between the sensor output values and the appropriate control parameter values is decided at the design stage and this relationship does not change once it has been decided.
Accordingly, in order to achieve uniformity of quality in terms of picture quality and density, etc., as the final objective using the picture-quality control methods of the kind set forth above, a mean having some latitude is taken of the demands made by all users and the mean must be adopted as being representative of the appropriate value. Consequently, since the appropriate values are merely the representative values set at the time of shipment, there will always be some users who are dissatisfied with the picture quality obtained. A similar problem arises even in control for automatic adjustment of copy density for dealing with the density of the original document. Such control is employed widely in the latest copying machines. Specifically, the problem is that when the automatic adjustment function is implemented, copies always appear somewhat faint. Consequently, even though the automatic adjustment function is intended to be convenient, there are only a few users who make the adjustment manually rather than utilize the automatic adjustment function.
Further, in the case of a copying apparatus of the electrophotographic type, the parameters which affect picture quality are highly numerous and a variation in picture quality owing to the passage of time and slight differences in the characteristics of various components are unavoidable.
Thus, the conventional image forming apparatus still possess a variety of shortcomings.